Rhamnus tree named ‘SMNRFBT’

ABSTRACT

A new and distinct  Rhamnus  cultivar named ‘SMNRFBT’ is disclosed, characterized by narrow leaves, good branching and dense foliage. The new variety is a  Rhamnus , normally used for outdoor ornamental purposes.

Latin name of the genus and species: Rhamnus frangula.

Variety denomination: ‘SMNRFBT’.

BACKGROUND OF THE INVENTION

The new Rhamnus cultivar is a product of a naturally-occurring whole plant mutation discovered by the inventor, Timothy Wood, in Grand Haven, Mich. The parent is the commercial variety Rhamnus ‘Ron Williams’, U.S. Plant Pat. No. 14,791.

The new variety was found and selected in Spring of 2017 by the inventor in a group of seedlings in a nursery in Grand Haven, Mich.

Asexual reproduction of the new cultivar has been performed by softwood cuttings. This was first performed at the same nursery in Grand Haven, Mich. in Spring 2017, and has shown that the unique features of this cultivar are stable and reproduced true to type in multiple successive generations.

SUMMARY OF THE INVENTION

The cultivar ‘SMNRFBT’ has not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment such as temperature, day length, and light intensity, without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘SMNRFBT’ These characteristics in combination distinguish ‘SMNRFBT’ as a new and distinct Rhamnus cultivar:

-   -   1. Narrow leaves.     -   2. Dense foliage.     -   3. Good branching.

PARENT COMPARISON

Plants of the new cultivar ‘SMNRFBT’ are similar to plants of the parent in most horticultural characteristics; however, plants of the new cultivar ‘SMNRFBT’ differ in the following;

-   -   1. The new variety has narrower leaves than the parent.     -   2. The new variety has better branching toward the base than the         parent.     -   3. The new variety has denser foliage than the parent.

COMMERCIAL COMPARISON

Plants of the new cultivar ‘SMNRFBT’ are comparable to Rhamnus ‘SMNRFBL’ co-pending, having application Ser. No. 16/602,606. The two Rhamnus varieties are similar in most horticultural characteristics; however, the new variety ‘SMNRFBT’ differs in the following;

-   -   1. The new variety has narrower leaves than this comparator.

BRIEF DESCRIPTION OF THE PHOTOGRAPH

The accompanying photograph illustrates in full color a typical plant of ‘SMNRFBT’ in a 2 gallon pot. Age of the plant photographed is approximately 2-3 years old from a rooted cutting. The photograph was taken using conventional techniques and although colors may appear different from actual colors due to light reflectance it is as accurate as possible by conventional photographic techniques.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The Royal Horticultural Society Colour Chart 2015 except where general terms of ordinary dictionary significance are used. The following observations and measurements describe ‘SMNRFBT’ plants grown in a poly greenhouse during July 2017, in Grand Haven, Mich. The growing temperature ranged from approximately 18° C. to 27° C. during the day and from approximately 5° C. to 10° C. during the night. General light conditions are normal sunlight and numerical values represent averages of typical plant types.

-   Botanical classification: Rhamnus frangula ‘SMNRFBT’.

PROPAGATION

-   Type of propagation typically used: Softwood cuttings. -   Time to initiate roots: 12 days in Summer. -   Time to produce a rooted cutting: 3 months in Summer. -   Root description: Thin to thick, fibrous, moderately dense, freely     branching. Tan to brown in color, not accurately measured with     R.H.S. Chart.

PLANT

-   Plant type: Perennial deciduous shrub. -   Age of plant described: 2-3 years old from a rooted cutting. -   Container size: 3 gallon container. -   Overall plant shape: Very upright, columnar. -   Growth habit: Upright. -   Plant spread: 70 cm. -   Plant height: 144 cm. -   Plant vigor: Good. -   Branching habit: Freely branching from the bottom. -   Length of primary lateral branches: 80 cm. -   Diameter of lateral branches: 7 mm. -   Quantity of lateral branches: Over 50. -   Stem:     -   -   Color.—RHS Grey 201A.         -   Shape.—Round.         -   Appearance.—Glabrous, smooth.         -   Strength.—Strong.         -   Aspect angle.—65-75°.         -   Pubescence.—No. -   Internode length: 0.5-2.5 cm.

FOLIAGE

-   Leaf:     -   -   Arrangement.—Alternate, single.         -   Average length.—14.5 cm.         -   Average width.—16 mm.         -   Shape of blade.—Linear.         -   Apex.—Acute.         -   Base.—Cuneate.         -   Margin.—Irregular, undulate.         -   Texture of top surface.—Glabrous, smooth.         -   Texture of bottom surface.—Glabrous, smooth.         -   Color.—Young foliage in Spring upper side: RHS Green 137A.             Young foliage in Spring under side: RHS Green 137C. Mature             foliage upper side: RHS Green 137A. Mature foliage under             side: RHS Green 137C. Fall foliage upper side: Near RHS             Yellow 7B. Fall foliage under side: Near RHS Yellow 7C.         -   Venation.—Type: Pinnate. Venation color upper side: RHS             Yellow-Green 153D. Venation color under side: RHS             Yellow-Green 144D.         -   Petiole.—Length: 1.25 cm. Diameter: 1.5 mm. Texture, upper             side: Smooth, some pubescence. Texture, under side: Smooth,             some pubescence. Color, upper side: RHS Yellow-Green 152B.             Color, under side: RHS Yellow-Green 144D.

FLOWER

-   Arrangement: Small, single rotate flowers arranged in axillary     clusters, not persistent, inconspicuous. -   Flowering habit: Small, inconspicuous clusters. -   Natural flowering season: June to July. -   Flowers per inflorescence: 3-6 per cluster. -   Flowers and buds per plant: 20. -   Individual flowers:     -   -   Type.—Rotate.         -   Quantity.—0-3 per lateral stem.         -   Diameter.—4 mm.         -   Length.—4 mm.         -   Aspect.—Upward, outward.         -   Persistence.—Self-cleaning.         -   Fragrance.—None. -   Petals:     -   -   Arrangement.—Rotate.         -   Number.—5.         -   Shape.—Narrowly deltoid.         -   Margin.—Entire.         -   Tip shape.—Acute.         -   Base shape.—Truncate.         -   Length.—1.5 mm.         -   Width.—1.5 mm.         -   Texture.—Upper: Smooth. Lower: Smooth.         -   Color.—When opening: Upper surface: RHS Green-White 157A.             Under surface: RHS Greyed-Orange 177A. Fully opened: Upper             surface: RHS Green-White 157A. Under surface: RHS             Green-White 157A. -   Bud:     -   -   Quantity.—0-3 per lateral stem.         -   Shape.—Globose.         -   Length.—3 mm.         -   Diameter.—3 mm.         -   Color.—RHS Green 139D. -   Petaloids: Not observed. -   Sepals: Not observed. -   Peduncle:     -   -   Length.—5 mm.         -   Diameter.—<1 mm.         -   Texture.—Smooth.         -   Angle.—15°.         -   Color.—RHS Green 139D.         -   Strength.—Weak. -   Pedicel: None.

REPRODUCTIVE ORGANS

-   Stamens:     -   -   Number.—5.         -   Filament length.—1 mm.         -   Filament color.—RHS Green 139D.         -   Anthers.—Shape: Oblong. Length: 1 mm. Color: Brownish, too             small to measure with R.H.S. chart.         -   Pollen.—Scant. -   Pistil:     -   -   Number.—1.         -   Length.—1 mm.         -   Style.—Length: 1 mm. Color: RHS Green 139D. -   Stigma:     -   -   Shape.—Spherical.         -   Color.—RHS Green 139D.         -   Ovary color.—RHS Green 139D.

OTHER CHARACTERISTICS

-   Fruits and seeds: Not observed to date. -   Disease/pest resistance: Neither resistance nor susceptibility to     normal diseases and pests of Rhamnus observed. -   Temperature range: Observed to tolerate a temperature range from     −28° C. to 35° C. Root hardy to −28 C, top of the plant does die     back to the ground. 

What is claimed is:
 1. A new and distinct cultivar of Rhamnus plant named ‘SMNRFBT’ as herein illustrated and described. 